🚀 go-pugleaf

nevin@CS.Arizona.EDU (Nevin ":-]" Liber) writes:

>In article <kevinbDMCMIy.B26@netcom.com>, kevin@frobozz.sccsi.com (Kevin
>Brown) wrote:
>
>> Fine.  Then try running a "brain-dead" program like this instead:
>
>>         main()
>>         {
>>             while ( there_is_useful_work_to_be_done )
>>             {
>>                 do_the_computationally_intensive_useful_work();
>>             }
>>             display_the_results();
>>         }
>
>> where there_is_useful_work_to_be_done remains true for long periods of
>> time (minutes, hours, perhaps even days).
>
>So, you can't figure out how to get this to work well on a Mac, eh? 
>Hmmmm...  <in deep thought for 4.2 seconds>  How about putting a
>WaitNextEvent() call in one of the inner loops of
>do_the_computationally_intensive_useful_work();?

Sounds easy, doesn't it?  Unfortunately, it's a little bit more complicated:

- If you put it in an inner loop, you risk to spend more cpu time in 
  WaitNextEvent() than in doing real work.

- If you put in an outer loop, you risk to have a system with a poor
  interactive response, once the cpu-bound process has got the cpu.

- Even if you tune it well on your system, it won't work as well on a
  slower machine or on the same machine when you restructure the program.

>I can't wait to see your next completely contrived example that you can't
>figure out how to solve that the rest of us can trivally solve.

Trivial solutions are not necessarily good solutions.

CMT just doesn't cut it well for cpu-bound applications running in
background, which shouldn't care at all about scheduling issues, which
aren't their business in the first place.

Dan
-- 
Dan Pop
CERN, CN Division
Email: danpop@mail.cern.ch 
Mail:  CERN - PPE, Bat. 31 R-004, CH-1211 Geneve 23, Switzerland